The present invention pertains to printed circuit boards and more particularly to simplify the providing of security to personal computer (PC), industrial computer or work station circuit boards with a secure bus arbiter or controller that allows or denies data access to the computer data bus.
Computer systems often handle classes of data that must not be permitted to intermingle due, for instance, to their security classifications, or for national security applications, or due to the criticality of their data content, such as in electronic transfer of money in banking applications or such as in power plant remote control for safety.
An isolated path must be established for transmitting a given class of data between elements of the computer system with assurance that the data has been transmitted from the proper source, has been received by an authorized recipient and that unauthorized elements of the system have not intercepted or altered the data.
Printed circuit boards typically have various computer functions and interface with data lines through what is called the backplane. The backplane where the card plugs into is also referred to as a motherboard.
Prior art for providing computer data line security has been to embed special controller circuitry or arbiter functions in the motherboard. The security circuitry is embedded between the printed circuit board interface and the computer data bus of the motherboard.
An arbiter function controller in the motherboard determines what cards are allowed access to the computer data bus to perform secret, classified or non-secret sensitive data handling such as money transfer, control of a nuclear reactor or similar safety related data. The arbiter function controller controls access to the computer data bus for each of the cards in secure or sensitive operations.
Each of these boards could be a different configuration and would require different treatment in the motherboard for providing secure functions. Modification of existing computer motherboards to incorporate a secure bus arbiter function would be a major undertaking.
Accordingly, it would be advantageous to have a replaceable arrangement that provides a secure bus arbiter module that is useable with all commercial off the shelf computer motherboards and backplanes. This would aid in being able to readily provide security with data lines for classified or sensitive data both when designing new data processors and especially for computers already in use.